S. Kawabata

Theoretical study of reflection spectroscopy for superconducting quantum parametrons

  1. S. Masuda,
  2. A. Yamaguchi,
  3. T. Yamaji,
  4. T. Yamamoto,
  5. T. Ishikawa,
  6. Y. Matsuzaki,
  7. and S. Kawabata
Superconducting parametrons in the single-photon Kerr regime, also called KPOs, have been attracting increasing attention in terms of their applications to quantum annealing and universal
quantum computation. It is of practical importance to obtain information of superconducting parametrons operating under an oscillating pump field. Spectroscopy can provide information of a superconducting parametron under examination, such as energy level structure and occupation of energy levels, and also useful information for calibration of the pump field. We theoretically study the reflection spectroscopy of superconducting parametrons, and develop a method to obtain the reflection coefficient. We present formulae of the reflection coefficient, the nominal external and the internal decay rates, and examine the obtained spectra.
arxiv pdf

Design of Quantum Annealing Machine for Prime Factoring

  1. M. Maezawa,
  2. K. Imafuku,
  3. M. Hidaka,
  4. H. Koike,
  5. and S. Kawabata
We propose a prime factoring machine operated in a frame work of quantum annealing (QA). The idea is inverse operation of a quantum-mechanically reversible multiplier implemented with
QA-based Boolean logic circuits. We designed the QA machine on an application-specific-annealing-computing architecture which efficiently increases available hardware budgets at the cost of restricted functionality. The circuits are to be implemented and fabricated by using superconducting integrated circuit technology. We propose a three-dimensional packaging scheme of a qubit-chip / interposer / package-substrate structure for realizing practically-large scale QA systems.
arxiv pdf